Electrical cut-out



Nov. s, 1938. T B KE AIE 2,135,787

ELECTRICAL CUT-OUT Filed March 29, 1937 2 Sheets-Sheet 1 Patented Nov. 8, 1938 UNITED STATES PATENT OFFICE ELECTRICAL CUT-OUT Application March 29, 1937, Serial No. 133,565

10 Claims. (01. 200-118) This invention relates to electrical cut-outs, and with regard to certain more specific features, to electrical cut-outs for constant-current circuits and the like.

The invention is an improvement upon the construction shown in my patent application, Serial No. 66,179, filed February 28, 1936, for Fuse, which resulted in Patent Number 2,077,207, dated April 13, 1937, and is adapted for improved use in constant-current circuits, such as shown" in the United States patent of R. R. Pittman, Number 2,068,510, dated January 19, 1937.

Among the several objects of the invention may be noted the provision of a sliding-tube type of cut-out of a very simple and reliable form; and the provision of a cut-out of the class described in which the contacts are independently sprung, thereby increasing the reliability of contact and decreasing the liability of derangement. Other objects will be in part obvious and in part pointed out hereinafter.

The invention accordingly comprises the elements and combinations of elements, features of construction, and arrangements of parts which will be exemplified in the structures hereinafter described, and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings, in which are illustrated several of various possible embodiments of the invention,

Fig. 1 is a side elevation of a cut-out embodying the invention, showing the device in an open and blown position;

Fig. 2 is a front elevation of Fig. 1;

Fig. 3 is an enlarged vertical section showing the apparatus in closed position;

Fig. 4 is a view similar to Fig. 3 but on a reduced scale, and showing certain parts in an alternate position and in elevation; and,

Fig. 5 is a horizontal section taken on line 5-5 of Fig. 4.

Similar reference characters indicate corresponding parts throughout the several views of the drawings.

As stated in said Pittman Patent 2,068,510, on page 2, column 2, lines 67-75, there may be used for the mechanical contrivance of that patent (for mechanically disconnecting the main and branch circuits upon blowing of the fuse link), a device such as that shown in my said application, Serial No. 66,179 (Patent 2,077,207) That is, the pivoted leg type of fuse holder, such as shown in the Patent 2,068,510, may have substituted therefor the sliding tube type of fuse holder shown in the Patent 2,077,207. The present disclosure comprises improvements upon the sliding tube type of fuse holder of my Patent 2,077,207, for perfecting its application to the conditions set forth in said Patent 2,068,510, as well as to analogous conditions.

Referring now more particularly to Fig. 1, there is shown at numeral an insulating box made of porcelain or like material having supporting means 3 molded therein. This box I has a closed back 5, a closed top 1, closed sides 9 and an open front and an open bottom, as indicated at numerals II and |3,respectively.

The open front ii is adapted to be closed by means'of a door I, also made of insulating material, pivoted at i1 and adapted to swing from the suspended position shown in Figures 1 and 2, to the closed-position shown in Figures 3-5. This door it carries a ring I9 for the purpose of manipulation.

Molded to the inside of the back wall of the box, or cemented therein, are main-circuit terminals 2| and 23 having wire-receiving sockets 25 which may be reached with the necessary wires through openings 27 in the side walls of the box. Below the main-circuit terminals 2| and 23, but separate therefrom, is held a pad 29 which carries extension horns 3|. Pivoted independently and respectively to the circuit contacts 2| and 23 are .contact arms 39 and 33, respectively, which are electrically connected to the respective line terminals 2| and 23 by flexible wires 35. The contacts 39 and 33 are normally pressed downwardly against said horns 3| by means of springs 31 reacting from extensions 39 from said line terminals 2| and 23.

From the above it will be seen that when the contacts 30 and 33 are free to be depressed by the spring 37, that they contact the horns 3|, and through the pad 29 cause an electrical connection from one of the line terminals 2| to the other line terminal 23, and vice versa.

Molded near the open bottom of the box and on its back are branch-circuit terminals 4| and l3 which carry pivoted thereto contacts 45 and 41. The contacts 45 and 41 are normally pressed downwardly respectively by springs 49 which react from extensions 5| of the terminals II or 43, as the case may be. Contact screws 50 are associated with sockets for receiving branch-circuit wires, the sockets being reached through openings 53 in the sides of the box adjacent said sockets.

At the upper end and on the inside of the door i5 is rigidly fastened a conducting head 55 into which is threaded and from which rigidly extends a downwardly directed tube 51 having an open lower end 59. The tube 51 and the door I5 thus become relatively immovable.

The upper end SI of the tube.51 extends into a socket 63 of said head 55. Threaded to the head 55 is an enclosing conducting cap 85 having means for holding a film type of cut-out element 61 which consists of spaced conducting means with a calibrated paper or similar film therebetween adapted to resist current flow under normal conditions. An insulating sleeve 1I prevents the film cut-out 61 from electrically contacting the side walls of openings 63. Below the film type of cutout 61 is the head 69 of a fuse link which is carried on the end of the tube 51 in the recess 63. Inasmuch as the tube 51 extends above the bottom of the recess 63, it insulates the cut-out 61 from electrical contact with the inside of member 55. The fuse link is denoted as a whole by the numeral 13 and-extends downwardly through the tube 51 and out of its open lower end 59. The type of fuse link may be of the class shown in United States Patent 2,067,577, issued January 12, 1937 to Carl E. Mosley and myself, or other satisfactory types.

Slidably mounted on the door I5 is a carriage strip 15 which slides under a guide 11 and has fastened at the lower end thereof a ring 19 which forms the lower end of a contact or conductor 8I which is clamped at its middle 83 to an outer insulating tube 85. At its upper end, the carriage 15 is fastened near the upper end of said conductor 8|, as shown at numeral 81. By this means the insulating tube 85 may move upwardly and downwardly with the carriage 15. The movable insulating tube 85 (on said carriage 15) spacedly surrounds the insulating tube 51 (rigid on the door I5).

As shown in Figures 1, 2 and 4, the conductor 8i carries an upper gudgeon 89 and a lower gudgeon 9I which, when the door I5 is swung into closed position, are adapted to contact with and become nested respectively in notches in the contacts 30 and 45. The lower gudgeon 9I engages the lower contact 45, and the upper gudgeon 89 engages the upper contact 30. In engaging the upper contact 3I, the gudgeon 89 also lifts this contact 30 clear of the respective horns 3|. This breaks the circuit connection with the contact 33 and .closes the circuit through the conductor 8I to contact 45. Current may under these conditions flow from the gudgeon 9I, through contact 45 and to the branch circuit wire connected to the contact 4|. The other side of the branch circuit being connected to the other contact 41, it remains to have provided with the tube 85 means for carrying said current back to the main-circuit contact 33, as it may be seen to be necessary from said Pittman Patent 2,068,510.

The above is accomplished by providing a lower gudgeon 95 opposite the gudgeon which gudgeon 95 passes through the insulating tube 85 and into the interior thereof where it is fastened to a conducting strip 91. The strip 91 passes upwardly through the tube to a gudgeon 99 which extends outwardly through the insulating tube 85 opposite said upper gudgeon 89. The inside conducting strip 91 passes on upwardly and out of the tube 85 where it is riveted to a flat coil spring I05 as shown at I03. The coil spring I05 is wrapped about the tube 51 and,-when the tube 85 is pushed upwardly by fastening the fuse link 13 at 93, as shown in Fig. 3, is adapted to electrically contact the conducting member 55. Under these conditions the fuse link 13 may carry potential to the film cut-out 61, because the lower end of the fuse link 13 is fastened as shown at 93 to the lower end of the conductor 8I, the tube 85 having been forced up as shown.

Operation of the device is as follows:

By swinging the door, I5 downwardly as shown in Figures 1 and 2, it may be removed from the pivot I1. By removing the cap 65, the fuse link 13 may be threaded through the washer H in the socket 83 and threaded through the inner insulating tube 51. The lower flexible portion of the link passes outwardly through the opening 59 and through the lower opening I01 of the outer tube 85. Then by doubling the link back and fastening it at the fastening 93, it can be made to hold up the outer tube 85 so that the spring I05 is compressed against and contacts the conducting member 55. This also has the effect of holding the gudgeons 9|, 95 and 89, IM in upward positions when the door is closed.

As the door is closed, the upper gudgeons 89 and 99 contact the contacts 30 and 33,1'espectively, while the lower gudgeons 9I and 95 contact the contacts 45 and 41, respectively. Current then flows from the main circuit into the contact 30, through gudgeon 89, down through the conductor 8I', out of gudgeon 9|, through contact 45, around the branch circuit, back to the contact 41, through the gudgeon 95, into the outer tube 85, up along the inside conductor 91, out through the gudgeon 99, to the contact 33 and back to the main circuit.

As stated in said Patent 2,068,510, there is used in the main circuit a constant-current transformer. Thus if a break occurs in the branch circuit, its resistance is raised practically to infinity, or, in case of a ground, it leads to a relatively high value, which immediately causes the apparatus in the main line circuit for maintaim ing constant current to increase the voltage, whereupon the film of the film cut-out 61 is punctured so as to permit current to flow as follows:

Starting at gudgeon 9|, it flows through the connector 93, fuse link 13, up through the voltage-punctured film cut-out 81, cap 65, conductor member 55, spring I05, conductor 91, gudgeon 99, contact 33 and back to the main line. This voltage causes a current to flow in the fuse link 13 which is calibrated to fuse under the value of the constant current carried. This releases the holding effect of the link on the outer tube 85, which promptly drops and carries with it all of the gudgeons 9|, 95, 89 and 99, as well as the spring I 05. Immediately the gudgeons 89 and 99 clear from the notches in their contacts 30 and 33, letting said contacts drop down upon the horns 3| to close and maintain the main circuit through the pad 29. At the same time the gudgeons 9I and 95 drop away from the contacts 45 and 41, thus entirely disconnecting the branch circuit. This condition is shown in Fig. 4. If the box I is sloped forwardly somewhat, the door I5 automatically swings open, that is, if it is not otherwise held shut.

If it be desired that the door not swing open under disconnecting conditions, a friction spring I09 is fastened beneath the member 55. These prongs may be adjusted to frictionally engage the side walls of the box I upon closure of the door I5. The operation with this spring in place and adjusted as suggested is otherwise the same as above described, except that when the box is sloped forwardly the door will not open, except when pulled open. The door-holding action of spring I09 is optional according to the adjustment of the spring thereof.

Re-fusing and re-connection is made by removing the door and applying a new fuse link and a new film cut-out member 61.

Among the advantages of the invention may be noted the provisions of means whereby all fuse holder elements on the door l are completely disconnected from any contact with any circuit after the fuse is blown. This means that there is absolutely no danger in touching any exposed part of the cut-out after it has blown, because it is impossible for any current to reach dangerous points. All of the contacts 30, 33, 45 and 41 are entirely isolated from physical contact with anything connected on the door l5. Suitable stops prevent unlimited descent of the contacts 45 and 41.

An advantage of the pivoted form of line terminals with the biasing coil spring is that the lineman cannot readjust the tension in the spring as is done with the ordinary leaf spring now used. The coil springs are not as likely to get out of order as are the leaf springs. Each line terminal having a pivoted arm operating independently assures that all contacts are thoroughly made, each independent of the other.

In view of the above it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As many changes could be made in carrying out the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. In a cut-out, line terminals, a movable support, a fuse carrier on said support comprising a conducting head having means for fastening a fuse, an insulating tube extending from said head, a second insulating tube slidably arranged over said first insulating tube, a pair of spaced conducting members secured to said second tube and extending longitudinally between the respective ends of said tube, contacts secured adjacent each of the respective ends of said conducting members and adapted to contact with said line terminals, resilient contact means between the upper end of one of said conducting members and said conducting head, a fuse within said first-named tube, a dielectric element serially connected with said fuse, said dielectric element and fuse being connected between the end of one of the conducting members and said conducting head.

2. In a cut-out, a fuse carrier comprising a conducting head, a rigid insulating tube extending from said head, a second insulating tube slidably arranged over said first insulating tube, a pair of spaced conducting members secured to said second tube, contacts secured to said conducting members, contact means between one of said conducting members and said conducting head, a fuse link within said first named tube members secured to said second tube, contact means between one of said'conducting members and said conducting head, a dielectric element carried by the hollow in said conducting head and serially engaging said fuse link, the series arrangement including said fuse link and said dielectric element being connected between one of the conducting members and the conducting head.

4. A cut-out comprising main line terminals and branch line terminals, a fuse holder, a movable support therefor, said fuse holder comprising a conductor held to said movable support and having a socket, an insulating tube rigidly supported in said conducting element a second insulating tube telescoping the first insulating tube, said second tube having pairs of gudgeons and respective connecting conductors between the gudgeons of each pair, the gudgeons being adapted to contact said line terminals to electrically connect the main line terminals and the branch line terminals by pairs, one pair of gudgeons be ing connected by said fuse with said conductor which is held on the movable member to hold said second tube in a circuit-closing position of its gudgeons, said fuse when blown releasing said gudgeons from their circuit-closing positions.

5. A cut-out comprising a box, main line terminals in said box and branch line terminals therein, a door, a fuse holder comprising a conductor socket held to said door, an insulating tube held for rigid support to said conductor socket, a second insulating tube telescoping the first insulating tube, said second tube having pairs of gudgeons and respective connecting conductors between the gudgeons, the gudgeons being adapted to contact said line terminals to "electrically connect the main line terminals and the branch line terminals by pairs, one pair of gudgeons being separably connected with said conductor socket, fusible means potentially connecting said conductor socket and the other pair of gudgeons, said fuse when blown releasing the second tube with all of its gudgeons from their circuit-closing positions.

6. In a cut-out, a movable support, a fuse holder on said support comprising a conducting member held to the support, said conducting member having a socket, an inner insulating tube rigidly held to said conducting support, an outer insulating tube movable with respect to the inner tube, said outer tube having separate conductors thereon, and resilient means connecting one conductor with said conducting socket in one position of the outer tube, but being electrically separable in another position of the outer tube.

7. In a cut-out, a support, a fuse holder on said support comprising a conducting member fixedly held to the support, an inner insulating tube rigidly held to said conducting support, an outer insulating tube movable with respect to the inner tube, said outer tube having separate conductors thereon, and resilient means connecting one conductor on the outer tube with said conducting member on the support in one position of the outer tube, but being electrically separated at another position of the outer tube. 8. In a cut-out, a support, a fuse holder on said support comprising a conducting member fixedly held to the support, an inner insulating tube rigidly held to said conducting support, an outer insulating tube movable with respect to the inner tube, said outer tube having separate conductors thereon, and resilient means connecting one conductor on the outer tube with said conducting member on the support in one position of the outer tube, but being electrically separated at another position of the outer tube, and a fuse link and film cut-out serially arranged and connecting electrically the other conducting element with said fixed conducting member, said fuse link when unfused being adapted to hold the outer tube so that said resilient means makes connection.

9. In a cut-out a conducting socket, an insulating tube rigidly fastened to said conducting socket, a second insulating tube telescoping said first one and carrying separate conductors, resilient means connecting one of said conductors with said conducting socket in one position of the outer tube and breaking contact in another position thereof, a fuse link, a film cut-out, said fuse link and said film cut-out being serially arranged between the other conducting member and said conducting socket.

10. In a cut-out a conducting socket, an insulating tube rigidly fastened to said conducting socket, a second insulating tube telescoping said first one and carrying separate conductors, terminal engaging elements associated with the conductors, line terminals therefor, resilient means connecting one of said conductors with said conducting socket in one position of the outer tube and breaking contact in another position thereof, a fuse link, a film cut-out, said fuse link and said film cut-out being adapted to be serially arranged between the other conductor and said conducting socket, said fuse link in unblown condition holding the outer insulating tube telescoped toward the inner tube and in a blown condition permitting movement of said outer tube to a point where said terminal engaging elements are separated from said line terminals.

THEODORE BIRKENMAIER. 

